Pump structure



Feb- 9, 1943 J. F. HoFFr-:R 2,310,370 v PUMP S TRUCTURE James E HoffefrlFeb. 9, 1943. J. F. Hor-FER PUMP STRUCTURE Original Filed May '7, 1938'Jmea' f? Hoffe"Y B @by M y' W ATTORNEY.

2 Sheets-Sheet 2 Patented Feb. 9,

Cell- Corporation, Detroit, Mich., a

tion of Michigan Original application May 7,

206,509. lDivided, 8.11

1938, Serial` No.

d this application July 8, 1940, Serial N0. 344,343 v tcl; s-'37)' 4 endof the housing'li, and is formed with a cen# 21 Claims.

. The present invention relates to improvements in pump structures andhas particular reference t0 a pump structure adapted for supplying f uelin metered charges and under pressure to' an internal combustion engine.

One of the objects of the invention is to provide a new and improvedpump structure comprising a relatively high pressure delivery pump, r I

and a primary pump for supplying iiuidunder a relatively low pressure tothe inlet of the first mentioned pump and also for returning uid leakagefrom the first mentioned pump Awith the normal uid supply to' the inlet.f

Another object is to provide, a novel pump structure of the foregoingcharacter inwhich the two pumpsare connected in a unitary structure andare driven in timed. relation and in ,which the primary pump has anauxiliary pump vfor in-v troducing fluid leakage from the interior ofthe delivery pump into the primary pump.

In the accompanying drawings, Figure .1, is a side elevational viewpartially in longitudinal section of a pump structure embodying thefeatures of my invention. y

Fig. 2 is a fragmentary transverse sectional view taken along line 2-2of Fig. 1.

tral bore 6 and with a plurality of parallel pump cylinders 1 arrangedin annularly spaced'rela tin about .the bore. A mummy of pumppistons 8are reciprocably disposed Ain the cylinders 1 and are urged outwardly bycompression springs 9.v Mounted in the other endof the housing4 is adriving mechanism fo ee'cting reciprocation of the pistons 8 inunionnly'tlmedjsequence. This mechanism comprises a pluralityofactuatingplungers II reciprocably guldedinthe housing 4, and disposed in axialalignment and end abutting engagement respectively with the pistons 8.yA rotary swash plate I2 coats with the Fig. 3 is a fragmentarytransverse sectional view taken along line 3-3 of Fig. 1.

I Fig. 4 is an enlarged fragmentary sectional view of the auxiliaryleakage pump. v

The present application is a division of my copending application SerialNo. 206,509, filed May 7, 1938 (Patent No. 2,265,232).

Referring more particularly to the drawings, the pump structureillustrating the invention comprises generally a delivery pump I fordischarging uid under a relatively high pressure, and a primary pump 2for supplying or transferring fluid under a relatively low pressure tothe inlet of the delivery pump. rI he primary pump 2 serves also toreturn uid leaking from the `de- ,livery pump to the inlet ofthe latter,and for this purpose 4preferably includes an auxiliary pump 3 forintroducing the leakage iluid into the primary pump for mixture anddelivery with the normal uid supply.

The highpressure delivery pump I may be of any desired form or type, andis herein disclosed for purposes of illustration as an adjustablemetering and distributing fuel pumpl like that` disclosed vin UnitedStates Letters Patent to Carroll R.. Alden No. 2,156,933, issued May 2,1939.

Briefly described, the'Y delivery pump I comprises a housing 4 adaptedto be mounted on a suitable support. A cylinder body 5 is mounted in oneplungers II, and is operable by a central drive shaft I3 in axialalignment with the bore 6. The pressure ends ofthe pump spectively pastcheck valves delivery lines I5, and have individual inlet ports I6opening in a common transverse plane to the bore 6. A groove Il isformed in the periphery of the bore 6, and is open to an inlet passageI8 connected to a low pressure uid supply line I9. Mounted in the bore 6is a rotary valve member '20 having a relief area 2I adapted to eiiectcommunication between the ports I6 and the lgroove I1 and having anarrow land area 22 movable success'ively across the ports to 'closeeach'port during a predetermined portionof the working stroke of theassociated piston 8. The valve memberv20 is operatively connected to theshaft I3 for rotation thereby in timed'relation to the reciprovcation ofthepistons 8.

In operation,` predetermined quantities of a, relatively high pressureand in timed sequence to the delivery lines I5. lAny fluid leaking .fromthe closed ends o f the cylinders 1 along the pistons 8 or from' thegroove I1 inwardly along the valve member-20 will pass into the interiorof the housing 4 between the cylinder body 5 and the driving mechanism.

' The primary pump 2 comprises. a body 23 located withiny and integralwithA the bottom wall of a casing 24-which is open at the top and boltedto the underside of the pump housing I4. The interior of the casing 24is open to the pump Ahousing 4, and adapted to receive and collect anyfluid leaking into the latter from the pump body 5.

lThe body 23 is formed with a longitudinal pump cylinder 25 open atopposite ends tothe interior of the casing 24. A guide b0re'26 in spacedaxial alignment with the cylinder 25 cylinders 1 open re yI4 to aplurality of im is-l'dsed-'t the outer end by an end plate 28 suitablybolted in position.

Formed in the cylinder 25 intermediate itsends is a peripheral groove 29connected at opposite sides respectively through inlet vand outletvalves 30 and 3| to'supply and delivery passages 32 and 33. The inletvalve 30 comprises a bore defining a valve chamber,34 openingdownwardly' in one side of the body 23 and connected through a passage35 to the groove 29. A valve passage 36 intersects the supply passage 32and opens' lduit 42 adapted for connection with a. suitable source ofiiuid supply, such as a tank (not shownie- It will be understood thatthe valve 36 will open in responseto the intake pressure in the cylinder25.

The outlet valve 3| comprises a bore deilning a valve chamber 43 in theother side of the body 23, and closed at the outer end by a screw cap44.l

The chamber 43 intersects the delivery passage 33, and is connected tothe groove 29 through a valve passage 45 encircled by an annular yalveseat 46. A valve member 41 is slidably guided in the cap 44, and isnormally urged into engagement withdthe seat 46 by a compression spring46. It will be understood that the valve 3| will operi in response tothe delivery pressure ln the cylinder 25. The passage 33 opens to oneend of the casing 23, and is connected through a screw iltting 49.to theline or conduit |9 leading to the inlet of the pump I.

The pump 2 also comprises a piston having a head 50 and a cup-shapedguide 5l interconnected by an axial stem 52. and reciproeablerespectively in one end of the '.cylinder 25 and in the guide bore 26.Suitable openings 53 are formed in the connecting end wall of the guideto permit pressure relief in the bore 26. Preferably, the piston 50 isdriven by the pump'l and hence in timed relation to the pistons 3. Thedrive comprises -a rocker lever 54 mounted intermediate its ends on apin 55 in the casing 24 for oscillation about an axis extendingtransversely of the piston 50. The upper end of the lever 54 is rounded,and engages in a transverse notch 56 in the underside of the lowermostoperating plunger The lower end of the lever 54 is similarly rounded,and engages in an annular groove 51 denned by the piston head 50 and aspaced ilange 56 integral with the stem 52.

Extending reciprocably into the end Yoi the cylinder 25 opposite thepiston 50 is a pressure control plunger 59. This plunger is urgedinwardly by spring pressure, and in eiect consti; tutes a yieldable endwall for the pressure chamthrough the pump body 23 and the end wall 21and end plate 23 to the exterior of the casing 24 in parallel relation'to" thepinger 5t. V'and is normally in engagement with the adjacent endof the pump body. A priming lever 65 is pivotally mounted on a bracket66 on the end plate the valve .3| during the pressure stroke.

26, and is provided with a lug 61 in abutment with the outer end of therod 64. The lever 65 is normally heldin its outermost positionrbymeans-'of ajSPllllE 56. It will be evident that swinging the lever65'inwardly againstl the rod 64 will cause the stop 60 throng engagementwith the shoulder 62 to shift the pr ssure plunger 59 outwardly in apumppriming stroke.

-Any suitable spring means may be provided for urging the4 plunger 59inwardly. In the present instance, the 'plunger 59 is formed with anaxial bore 69 opening to the outer end. A iloat bushing 16, havinganinternal flange 1| deflning a.

spring seat, is slidable in the bore 69. A compres- Ision spring' 12 inthe bore 65 engages one side of the seat 1|. A similar spring13 engagesthe other lside of the seat 1| and a stationary seat 14 mounted in theadjacent end wall of the casing A24. The bushing 10 permits the use ofthe two relatively short springs 12 and 13 which will notA tendto buckleobjectionabiy or rub against the surface of the bore 69 as would belikely if a single long spring were employed in their stead. A thirdcompression spring 15, encircling the spring 13 and also engaging theseat 14, acts directly against the outer end of the plunger 5I. 'Ihethree springs 12, 13and 15 all tend to urge the plunger 59 inwardly, andare provided in lieu of one spring in order to obtain the desired thrustpressure plunger 56 is operable automatically to vary the displacementof the pump 2 in accordance with the requirements of the pump at apredetermined maximum pressure. If the maxlmum displacement of the pump2 is required, the springs 12, 13 and 15 will hold the shoulder 62 inengagement with the stop 60 to locate the pressure plunger 56 in itsinnermost position. In the event that the full displacement of the pump2 is notrequired, the pressure in the cylinder 25 will cause the plunger59 to'move outwardly during the pressure stroke of the piston 56 so thatonly part of the displacement of the piston will be discharged throughthe valve 3|. In the subsequent suction stroke, the plunger 56 will moveinwardly to maintain the uid in the cylinder 25 under the predeterminedmaximum discharge pressure until the shoulder 62 again engages the stop60, and thereafter ilmd in an amount suiilcient to'rell the cylinder 25will enter'through the valve 30. It will therefore 'be evident that thepump is self-relieving.

The function oi the hand lever 65 andassociated Darts is to permitmanual reciprocation of the plunger 59 independently of the piston 56for the purpose of priming the injection system without cranking theengine. Hand 4priming is resorted to when for. any reason the systembecomes air bound, for example, as a result of the fuel tank runningdry.' The priming is accom- TheV v 2,810,370 plished by'working thelever 65 a sufcient number of full strokes to expel the air and' to tillthe system with oil under maximumprimary .pump

pressure. Thereafter, the springs 12, 13 and 15 will fail to move theplunger 59 to the left', thereby automatically renderingithe handprimingf fluid into the cylinder 25 during the suction stroke of thepiston 50. In its preferred form, the pump 3 is built into the piston50, and specifically comprises an axial cylinder bore 16 opening throughthe stem 52 and havingradial inlet ports 11 opening to the groove 51.The inner end of the bore 16 is adapted to discharge through an outletvalve 18 into the cylinder 25. A pumpplunger- 19 is reciprocable in theouter end of the bore 16, and is provided with an external head 89normally held against the end plate 28 by a coiled compression spring8|.

During the pressure stroke of the piston 50, the plunger 19is relativelyretracted from the llore 16 to uncover the ports 11. If the fluid levelin the casing 24 is at or above the ports 11, the fluid will enter andfill the pressure end of the bore 16. During the subsequent intakestroke of the piston 50, the plunger-,19 will be forced into t e -bore16 in a pressure stroke to discharge the fluid past the valve 18. Thecapacity of the pump from entering the valve 18 and interfering withseating of the-valve member 90. In the event that the valve member 90fails to seat, the ref striction also serves to insure continueddelivery of fluid by the pump 2 so that when the pump.

structure is employed to supply fuelto'an engine the latter willnots'top for lack of fuel. I claim as myinvention:

1. A pump structure comprising, in..combina,

tion, a pump havinga chamber, a pump cylinder 4 open at one-end to saidchamber and having uid supply and discharge means connected to the otherend, a piston reciprocable in said cylinder and means in said chamberfor driving said piston, and a second pump driven from said lastmentioned means in timed relation to said first mentioned p ump and,operable to return fluid leaking from said cylinder into said chamberback to said fluid supply means of said rst mentioned pump.L

' 2. .A pump structure comprising, in combination, a pump having pumpingelements with fluid supply means and fluid discharge means and having anenclosing housing adapted to receive fluid 3 is sufliciently in excessof the normal leakage that the fluid level in the casing 24 will beautomatically maintained atthe ports 11.

The leakage pump plunger 19 is formed with a peripheral groove 82 whichis connected through radial bores 83 and7 an axial bore 84 to theinnerend of the plunger, and which is movable into registration with theinlet ports 11 at'the end of the pressure stroke to relieve the pressurein the cylinder bore 16. I'he relief or by-pass determines the end pointof pressure discharge by the Iplunger 19. Consequently, changes in thelength 'of stroke of the piston 59 as would be obtained by substitutionof swash plates I2. of different angularities, will not change theeifective capacity. of the pump 3. The effective portion of the pressurestroke of the lplunger 19 will remain constant l,

regardless of changes in the length of relative plunger travel. If thelevel of leakage fluid in the casing 24 is below the ports 11, thecylinder bore 16 will be charged with air., The relief or by-pass alsoserves to prevent excess movement of the plunger 19 from compressing theair to a pressure sufciently high to open the valve 18.

The valve 18 comprises a hollow body 85 threaded into an axial bore 86in the working end of .the piston and connecting with 'the secured inthe inner end of the body 85, and is clamped against the inner end Aedgeof the bore 16 to dene in effect the end-wall of the latter. The

memberl is formed with va restricted valve port bore 16. The restrictionof the portv 88 prevents large particles of dirt and other foreignmatter cylinder bore 16. A tapered member 81 is rigidly .60

leaking from said elements, and a second pump driven in timed relationto said firstmentioned pump and operable to `return fluid leaking vfromsaid elements back to said supply means.

3, A pump structure comprising,- in combination, .a relatively highpressure delivery pump having an inlet and an outlet, pumping meanstaking fluid from said inlet and discharging it to said outlet, arelatively low pressure pump having an inlet and having an outletconnected to said iirst mentioned inlet and having pumping means drivenin timed relation to said first mentioned pumping means, means forcollecting fluid leaking from both said pumping means, and n auxiliarypump driven in timed relation to said low pressure pump and operable totransfer fluid leaking from said two pumping means and collecting insaid last mentioned means to sai'dlow pressure pump for return with anormal supply of fluid to said rst mentioned inlet'.

4. A pump structurecomprising. in combina-A tion, alcasing having aninternaliiuid collecting i chamber and a pump cylinder, a pistonreciprocable in said cylinder, means for supplying uid to said cylinderandfor discharging fluid from said cylinder in response to the.reciprocation of said piston, and an auxiliary pump operl able by saidpiston and adapted to transfer uid from said chamber to said cylinder.

5. A pump structure comprising, in combina-'4A tion, a casing having aninternal fluid collecting chamber and a pump cylinder, a pistonreciprocable in said cylinder, means forsupplying uid to saidcylinderduring the suction stroke of 'said piston, means for discharging fluidfrom said cylinder in response to the pressure stroke of said piston,and an auxiliary pump operable in timed relation to said piston fordischarging fluid from said chamber to said cylinder only during the'suction stroke of saidl piston and independently of sad first mentionedmeans..

6. A pump comprising, in combination, a cas'- ing having an internalfluid collecting chamber cylinder, and a plunger relatively reciprocablein said auxiliary cylinder in response to the reciprocation oi' saidpiston and movable at the en'd of its v'suction stroke 'to uncover saidinlet ports.

7; 'A pump comprising, in combination, a casing having an internal fluidcollecting chamber and a body formed with a pump cylinder, means fordischarging duid under pressure from said cylinder, apiston reciprocablein said cylinder and formed with an axial auxiliary cylinder hav- :ingan inlet port opening to said chamber and having means including anoutlet check valve discharging to said pump cylinder, and a plungervrelatively reciprocable vin said auxiliary cylinder andavo pistonguided for power reciprocation in said cylinder, an axial cylinder boreopening to one end of said piston and having an inlet port in one side`open to said reservoir and an outlet discharging to said cylinder, apumpplunger extending reciprocably into said bore, and spring meansalternate pressure and intake strokes relative to returning fluidleaking from said elements back to said supply means.

9. In combination, a high pressure pump of the pulsating type havingpump elements withlow pressure pump of the constant pressure type forsupplying duid to said supply means and a pump for supplying duidleaking from said elements to said low pressure pump for return to saidsupply means.

10. In combination, a high pressure pump oi the pulsating type havingpump elements with duid supply means and duid discharge means. a lowpressure pump normally of the constant pressure type for supplying duidto said supply means, power drive means for operating said low pressurepump in timed relation to said high pressure pump, and means formanually camerating said low pressure pump independently oi' said highpressure pump to deliver duid to said simply means.

ll. In combination, a high pressure variable.

delivery pump of the pulsating type having pump elements with duidsupply means and duid discharge means, and a low pressure pump havingduid delivery means connected to said duid sup* 'pl'y means and havingself-relieving means for varying the, effective displacement andlimiting the delivery pressure of the duid displaced, whereby to providea volume delivery variable in accordance with the demands of said drstmentioned pump.

12. In a pump structure, in combination, a

pump cylinder having inlet and outlet means, a

4piston extending` sl'idably into one end of said iary cylinder, and inthe other direction `ot movement an intake phase in' said cylinder and adischarge phase in said auxiliary cylinder.

13. A pump structure comprising in combinationwith a duid reservoir. adxed cylinder mountsaid bore as an incident to the reciprocation of saidpiston, said plunger uncovering said port at the end ot each intakestroke to admit duid from said reservoir to said bore, and covering saidport during each pressure stroke to' discharge duid under pressurei'r'om said bore.

14. A pump .structure 'comprising in cmbination with a duidreservoir, acylinder located horizontally in the bottom or -said reservoir, a pistonreciprocable at one end in said cylinder and having at the other end acylinder bore with an inlet port in one side open to said reservoir, anoutlet check valve opening from said cylinder bore to said cylinder, apump plunger extending for relative reciprocation into said bore, springmeans tending to urge said plunger out of said bore, said plungeruncovering said port at the end oi. each intake stroke to admit duidfrom said reservoir to said bore, and'means for relieving said bore tosaid reservoir at the end of the pressure stroke of said plunger.

l5. A pump comprising in combination with a duid reservoir, a cylinderbody mounted horizontally in the vbottom of said reservoir and guideded'horlzontally in the bottom oi said reservoir, a 75 ing an inlet portin one side open to said reser' voir, a pump plunger extendingreciprocably into said bore, spring means tending to urse said plungerout of `said bore and to maintain said plunger in a fixed position foralternate pressure and intake strokes relative to said bore as anincident lto the reciprocation of said body. said plunger uncoveringlsaid port at the end of each intake stroke to admit duid from saidreservoir to said bore., and means for discharging duid underpressure-from said bore in response to the pressure stroke of sai'dplunger.

16. A pump comprising in combination with a duid reservoir, a bodylocated horizontally in the bottom of said reservoir and having acylinder bore with an inlet port in one side open to said reservoir, apump plunger extending i'or relative reciprocation into said bore,spring means tedding to urge said plunger out oi said bore, said,plunger uncovering said port at the end of each intake stroke to admitduid from said reservoir to saidI bore, a discharge e having anoutwardly opening valve` seat and a restricted port opening from'isaidbore in spaced relation to said seat, an outlet check valve memberadapted to engage said seat, and spning means tending to hold saidmember against said seat with a pressure sudlcientto prevent liiting ofsaid member .v

by any gas pressure created in said bore.

17. In a pump structure, in combinationfa. high pressure pump having apump element with`-- ually operating said self-relieving means to effectthe delivery of fluid from said low pressure pump to said fluid supplymeans independently of operation of said low pressure pump by said powerdrive means.4

18. In a pump structure, in combination, a high pressure pump havingfluid supply means and fluid discharge means, a low pressure pump havinga cylinder, a pump piston reciprocable in one end of said cylinder and aself-relieving piston in the other end of said cylinder for limiting thedelivery pressure to provide a volum'e delivery variable in accordancewith the demands of said first mentioned pump, said cylinder havingfluid inlet means and having fluid outlet means' adapted to receive thefluid displaced by either of said pistons, power drive means foroperating said pump piston in timed relation to said high pressure pump,and means'for manually operating said self-relieving pistonindependently. of

. said power drive means.

.taking fiuid from said inlet and discharging it to said outlet, andmeans for collecting fluid leaking from said pumping means, a.relatively low pressure pump having an inlet and having anoutletconnected to said first mentioned inlet and having pumping meansdriven in timed relation to said first mentioned pumping means, and anauxiliary pump driven in timed relation to said low pressure pump andoperable to transfer fluid leaking from said first mentioned pumpingmeans and collecting in said second ment oned means to said low pressurepump for retur with a normal supply of fluid to said first mentionedinlet.

2l. A pump structure comprising, in combination, a metering pump havinga supply inlet and a delivery outlet, piston means adapted to adjustablyalter the effective displacement of said metering pump irrespective ofthe pressure in said delivery outlet, a second pump adapted to supplyfiuid to said supply inlet of said metering pump,.. said second pumpincluding a plunger having a constant length of stroke but of variableeffective displacement inversely responsive to the pressure of fluidsupplied by said second pump, a sump associated with said rst and secondpumps, and a third pump comprising a plunger of constant stroke andfixed effective displacement adapted to transfer fluid from said sump tothe supply inlet of said first pump against and irrespective of thepressure of fluid delivered by said second pump.

JAMES F. HOFFER.

